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Abstract:

A vibratory compactor machine includes a machine frame and a roller drum
rotatably coupled to the frame and rotatable about a drum axis oriented
generally traverse to the direction of travel of the machine. A vibration
assembly is disposed inside the roller drum. The vibration assembly
includes a first eccentric member and a second eccentric member rotatably
disposed in the roller drum and rotatable about a respective first and
second eccentric axes orientated perpendicularly to the drum axis. The
roller drum rotates about the drum axis independently of the vibration
assembly and the first and second eccentric members.

Claims:

1. A vibratory compactor machine comprising: a machine frame; at least
one cylindrical roller drum rotatably coupled to the machine frame and
rotatable about a drum axis oriented generally transverse to a direction
of travel of the vibratory compactor machine; and a vibration assembly
disposed inside the roller drum, the vibration assembly including a first
eccentric member and a second eccentric member, the first eccentric
member rotatably disposed in the roller drum about a first eccentric axis
and the second eccentric member rotatably disposed in the roller drum
about a second eccentric axis, the first eccentric axis and the second
eccentric axis oriented generally perpendicularly to the drum axis,
wherein the roller drum rotates about the drum axis independently with
respect to the vibration assembly including the first eccentric member
and the second eccentric member.

2. The vibratory compactor machine of claim 1, wherein the first
eccentric axis and the second eccentric axis are parallel to each other.

3. The vibratory compactor machine of claim 2, wherein the cylindrical
drum roller includes a first end and an opposite second end, the drum
axis extending between the first and second ends.

4. The vibratory compactor machine of claim 3, wherein the first
eccentric member and the second eccentric member are axially spaced apart
with respect to the drum axis and with the first eccentric member
disposed toward the first end of the roller drum and the second eccentric
member disposed toward the second end of the roller drum.

5. The vibratory compactor machine of claim 4, wherein the first
eccentric member and the second eccentric member rotate about the first
eccentric axis and the second eccentric axis, respectively, in opposite
directions of each other.

6. The vibratory compactor machine of claim 5, wherein rotation of the
first eccentric member produces a first eccentric force and rotation of
the second eccentric member produces a second eccentric force, and the
first eccentric member and the second eccentric member are in a phase
relationship such that the first eccentric force and the second eccentric
force generate a combined vibratory force generally along the direction
of travel.

7. The vibratory compactor machine of claim 6, wherein the phase
relationship between the first eccentric member and the second eccentric
member is such that the first eccentric force and the second eccentric
force cancel in a direction generally transverse to the direction of
travel and parallel to the drum axis.

8. The vibratory compactor machine of claim 1, further comprising a
bearing assembly supporting the vibration assembly within the roller drum
enabling independent rotation of the roller drum about the vibration
assembly.

9. The vibratory compactor machine of claim 8, wherein the vibration
assembly further comprises a drive motor for rotating the first eccentric
member and the second eccentric member.

10. The vibratory compactor machine of claim 9, wherein the drive motor
defines a motor rotation axis that is generally parallel to the drum axis
and generally perpendicular to the first eccentric axis and the second
eccentric axis, the drive motor drives a first bevel gear that operably
cooperates with a second bevel gear on the first eccentric member.

11. The vibratory compactor machine of claim 10, wherein the first
eccentric member includes a first transmission gear operably cooperating
with a second transmission gear on the second eccentric member to rotate
the second eccentric member.

12. The vibratory compactor machine of claim 11, wherein the vibration
assembly can pivot via the bearing assembly to adjust an angular
orientation of the first eccentric axis and the second eccentric axis
with respect to the direction of travel.

13. A method of compacting a surface, the method comprising: providing a
vibratory compactor machine including a cylindrical roller drum in
rolling contact with the surface, the roller drum rotatable about a drum
axis oriented generally perpendicular to a direction of travel of the
vibratory compactor machine; disposing a vibration assembly inside the
roller drum; the vibration assembly including a first eccentric member
rotatable about a first eccentric axis and a second eccentric member
rotatable about a second eccentric axis, the first eccentric axis and the
second eccentric axis oriented generally perpendicular to the drum axis;
rotating the roller drum independently about the vibration assembly;
inducing a vibratory force to the roller drum along the direction of
travel by rotating the first eccentric member and the second eccentric
member.

14. The method of compacting of claim 13, further comprising: rotating
the first eccentric member about the first eccentric axis to produce a
first eccentric force; and rotating the second eccentric member about the
second eccentric axis in an opposite direction to produce a second
eccentric force.

15. The method of compacting of claim 14, further comprising phasing
rotation of the first eccentric member and the second eccentric member so
that the first eccentric force and the second eccentric force induce a
combined vibratory force generally along the direction of travel.

16. The method of compacting of claim 15, further comprising phasing
rotation of the first eccentric member and the second eccentric member so
that the first eccentric force and the second eccentric force cancel in a
direction generally transverse to the direction of travel and parallel to
the drum axis.

17. The method of compacting of claim 13, further comprising pivoting the
vibration assembly to adjust an angular orientation of the first
eccentric axis and the second eccentric axis with respect to the surface.

18. A vibratory compactor for compacting a surface, the vibratory
compactor configured for permanent or detactable connection with a
machine adapted to travel over the surface, the vibratory compactor
comprising: a cylindrical roller drum for rolling contact with the
surface, the roller drum rotatably coupled to a frame connectable to the
machine, the roller drum rotatable about a drum axis oriented generally
transverse to a direction of travel of the machine; a vibration assembly
disposed inside the roller drum, the vibration assembly including a first
eccentric member rotatable about a first eccentric axis to produce a
first eccentric force and a second eccentric member rotatable about a
second eccentric axis to produce a second eccentric force, the first
eccentric axis and the second eccentric axis oriented generally
perpendicular to the drum axis and to the direction of travel; a bearing
assembly supporting the vibration assembly and enabling respective
independent rotation of the roller drum about the vibration assembly to
substantially maintain perpendicular orientation of the first eccentric
axis and the second eccentric axis with respect to the drum axis and the
direction of travel.

19. The vibratory compactor of claim 18, wherein the first eccentric
member and the second eccentric member rotate in a phase relationship
with each other and in opposite directions to each other such that the
first eccentric force and the second eccentric force combine to generate
a combined vibratory force generally along the direction of travel and
cancel in a direction generally transverse to the direction of travel.

20. The vibratory compactor of claim 19, wherein combined vibratory force
oscillates along the direction of travel as the first eccentric member
and the second eccentric member rotate approximately 180.degree. about
the respective first and second axes.

Description:

TECHNICAL FIELD

[0001] This patent disclosure relates generally to a machine for
compacting a material and, more particularly, to a vibratory compactor
machine with roller drums for traveling over and inducing a vibratory
force to a surface with the material to be compacted.

BACKGROUND

[0002] Compactors are machines used to compact initially loose materials,
such as asphalt, soil, gravel, and the like, to a densified and more
rigid mass or surface. For example, during construction of roadways,
highways, parking lots and the like, loose asphalt is deposited and
spread over the surface to be paved. One or more compactors, which may be
self propelling machines, travel over the surface whereby the weight of
the compactor compresses the asphalt to a solidified mass. The rigid,
compacted asphalt has the strength to accommodate significant vehicular
traffic and, in addition, provides a smooth, contoured surface that may
facilitate traffic flow and direct rain and other precipitation from the
road surface. Compactors are also utilized to compact soil or recently
laid concrete at construction sites and on landscaping projects to
produce a densified, rigid foundation on which other structures may be
built.

[0003] Various types of compactors are known in the art. For example, some
compactors include a rotatable roller drum that may be rolled over the
surface to compress the material underneath. In addition to utilizing the
weight of the roller drum to provide the compressive forces that compact
the material, some compactors are configured to also induce a vibratory
force to the surface. As can be appreciated, the vibratory forces assist
in working or compacting the loose materials into a dense, uniformly
rigid mass. To generate the vibratory forces, one or more weights or
masses may be disposed inside the roller drum at a position off-center
from the axis line around which the roller drum rotates. As the roller
drum rotates, the off-center or eccentric position of the masses induce
oscillatory or vibrational forces to the drum that are imparted to the
surface being compacted. In some applications, the eccentrically
positioned masses are arranged to rotate inside the roller drum
independently of the rotation of the drum.

[0004] For example, U.S. Pat. No. 7,213,479 describes a vibratory
mechanism in which two vibratory shafts are stored in a roll. The
vibratory shafts include one or more eccentric weights disposed thereon
and are configured to rotate inside the roll so that the eccentric
weights generate an oscillating or vibratory force. Inside the roll, the
vibratory shafts are parallel to each other and the rotational axis of
the roll with the first and second vibratory shafts arranged 180°
opposite each other with respect to the rotational axis of the roll.
Further, the vibratory shafts cooperate with each other to vibrate the
roll in various radial and tangential directions depending on the
direction that the shafts are rotated.

[0005] As can be appreciated, it may be possible to vibrate or oscillate
the roller drum in predetermined and particularized directions that
improve the rate and degree of compaction of the material, that is, to
focus the vibratory forces onto the surface being compacted. An opposing
concern is to minimize or isolate the vibrations of the roller drum to
avoid determinately effecting the operation of the compactor.

SUMMARY

[0006] The disclosure describes, in one aspect, a vibratory compactor
machine including a machine frame and at least one cylindrical roller
drum rotatably coupled to the machine frame so as to be rotatable about a
drum axis that is oriented generally transverse to a direction of travel
of the vibratory compactor machine. A vibration assembly is disposed
inside the roller drum. The vibration assembly may include a first
eccentric member and a second eccentric member where the first eccentric
member is rotatably disposed in the roller drum about a first eccentric
axis and the second eccentric member is rotatably disposed in the roller
drum about a second eccentric axis. The first eccentric axis and the
second eccentric axis are oriented generally perpendicular to the drum
axis. The roller drum is configured to rotate about the drum axis
independently of the vibration assembly including rotating independently
with respect to the first and second eccentric members.

[0007] In a further aspect, there is disclosed a method of compacting a
surface which involves a vibratory compactor machine that has a
cylindrical roller drum in rolling contact with the surface and rotatable
about a drum axis that is oriented generally perpendicular to a direction
of travel of the machine. The method includes disposing a vibration
assembly inside the roller drum where the vibration assembly includes a
first eccentric member rotatable about a first eccentric axis and a
second eccentric member rotatable about a second eccentric axis. The
first eccentric axis and the second eccentric axis are also oriented
generally perpendicular to the drum axis. The roller drum can be rotated
independently about the vibration assembly. According to the method, a
vibratory force can be induced to the roller drum generally along the
direction of travel by rotating the first eccentric member and the second
eccentric member within the roller drum.

[0008] In yet another aspect, the disclosure provides a vibratory
compactor for compacting a surface which is configured for permanent or
detactable connection with a machine adapted to travel over the surface.
The vibratory compactor includes a cylindrical roller drum for rolling
contact with the surface. The roller drum is rotatably coupled to a frame
that is connectable to the machine. The roller drum can rotate about a
drum axis oriented generally transverse to a direction of travel of the
machine. A vibration assembly is disposed inside the roller drum and
includes a first eccentric member rotatable about a first eccentric axis
to produce a first eccentric force and a second eccentric member
rotatable about a second eccentric axis to produce a second eccentric
force. The first eccentric axis and the second eccentric axis are
oriented generally perpendicular to the drum axis and to the direction of
travel of the machine. The vibratory compactor also includes a bearing
assembly supporting the vibration assembly and enabling respective
independent rotation of the roller drum about the vibration assembly to
substantially maintain perpendicular orientation of the first eccentric
axis and the second eccentric axis with respect to the drum axis and the
direction of travel of the machine.

BRIEF DESCRIPTION OF THE DRAWING(S)

[0009]FIG. 1 is a side plan view of a vibratory compactor machine
including one or more roller drums that are in rolling contact with a
surface to be compacted.

[0010]FIG. 2 is a cross-sectional view of the roller drum taken along
lines 2-2 of FIG. 1 that illustrates an embodiment of an internal
arrangement of the roller drum configured to generate vibratory forces.

[0011]FIG. 3 is a top plan view of the vibratory compactor illustrating
the directions in which the vibratory forces may combine or cancel.

[0012]FIG. 4 is side plan view of another embodiment of the roller drum
in which the vibration assembly may be pivoted in the roller drum to
adjust the angular position of the vibratory forces.

[0013]FIG. 5 is a perspective, cut-away view of another embodiment of a
vibratory compactor designed to be pushed before or trailed behind a
self-propelling machine.

DETAILED DESCRIPTION

[0014] This disclosure relates generally to a vibratory compactor machine
having one or more roller drums that are in rolling contact with a
surface to be compacted. Loose material, characterized as material which
can be further packed or densified, is disposed over the surface. As the
compactor machine travels over the surface, vibrational forces generated
by the compactor machine and imparted to the surface, acting in
cooperation with the weight of the machine, compress the loose material
to a state of greater compaction and density. The compactor machine may
make one or more passes over the surface to provide a desired level of
compaction. In one intended application, the loose material may be
freshly deposited asphalt that is to be compacted into roadways or
similar hardtop surfaces. However, in other applications, the material
may be soil, gravel, sand, land fill trash, concrete or the like.

[0015] Referring to FIG. 1, there is illustrated a compactor machine 100
of the self-propelled type that can travel over a surface 102 under its
own power. The compactor machine 100 includes a body or frame 110 that
inter-operatively connects and associates the various physical and
structural features that enable the compactor machine to function. These
features may include an operator's cab 112 that is mounted on top of the
frame 110 from which an operator may control and direct operation of the
compactor machine 100. Accordingly, a steering feature 114 and similar
controls may be located within the operator's cab 112. To propel the
compactor machine 100 over the surface 102, a power system 116 such as an
internal combustion engine can also be mounted to the frame 110 and can
generate power that is converted to physically move the machine. One or
more other implements may be connected to the machine. Such implements
may be utilized for a variety of tasks, including, for example, loading,
lifting, brushing, and may include, for example, buckets, forked lifting
devices, brushes, grapples, cutters, shears, blades, breakers/hammers,
augers, and others.

[0016] To facilitate control and coordination of the compactor machine
100, the compactor machine can include an onboard controller 118 such as
an electronic control module that includes a microprocessor or other
appropriate circuitry and can include memory or other data storage
abilities. The main unit of the controller 118 can be located in the
operator's cab 112 for access by the operator and can communicate with
the steering feature 114, the power system 116 and with various other
sensors and controls on the compactor machine. While the controller 118
illustrated in FIG. 1 is represented as a single unit, in other
embodiments the controller may be distributed as a plurality of distinct
but interoperating units.

[0017] To enable physical motion of the compactor machine 100, the
illustrated machine includes a first roller drum 120 and a second roller
drum 122 that are in rolling contact with the surface 102. For reference
purposes, the compactor machine 100 can have a typical direction of
travel indicated by arrow 124 such that the first roller drum 120 may be
considered the forward roller drum and the second roller drum 122
considered the rearward roller drum. The forward and rearward roller
drums 120, 122 can be cylindrical structures that are rotatably coupled
to and can rotate with respect to the frame 110. Because of their forward
and rearward positions and their dimensions, the forward and rearward
roller drums 120, 122 support the frame 110 of the compactor machine
(100) above the surface 102 and allow it to travel over the surface. The
roller drums 120, 122 are oriented generally traverse or perpendicular to
the direction of travel 124 of the compactor machine 100. It should be
appreciated that because the compactor machine 100 is steerable, the
forward direction of travel 124 may change bearing during the course of
operation but can be typically assessed by reference to the direction of
movement of the forward roller drum 120. In the illustrated embodiment,
to transfer motive power from the power system 116 to the surface 102,
the power system can operatively engage and rotate the rearward roller
drum 122 through an appropriate power train.

[0018] Referring to FIG. 2, there is illustrated the interior of the first
roller drum 120, however, it will be appreciated that the second roller
drum 122 can have the same or different construction. In particular, the
first roller drum 120 is an elongated, hollow cylinder with a cylindrical
drum shell 130 that encloses an interior volume 132. The cylindrical
roller drum 120 extends along and defines a cylindrical drum axis 134. To
withstand being in rolling contact with and compacting of the surface
102, the drum shell 130 can be made from a thick, rigid material such as
cast iron or steel. While the illustrated embodiments shows the surface
of the drum shell 130 as having a smooth cylindrical shape, in other
embodiments, a plurality of bosses or pads may protrude from the surface
of the drum shell to, for example, break up aggregations of the material
being compacted. The axial length of the cylindrical roller drum 120 is
delineated between a first side or first end 136 and an opposite second
side or second end 138. To enable the roller drum 120 to roll with
respect to the surface 102, the roller drum may be rotatably coupled with
the frame 110 of the compactor machine 100. To accomplish this, as
illustrated in FIGS. 1 and 2, the roller drum 120 is supported between a
bifurcated flange 126 having a first flange leg 128 and a second flange
leg 129 extending proximate to the first and second ends 136, 138 such
that the drum axis 134 is horizontal with respect to the surface 102.

[0019] To cause the roller drum 120 to vibrate and impart compacting
forces to the surface 102, a vibration assembly 150 that includes the
components of a mechanical vibratory system may be disposed inside the
interior volume 132 of the roller drum. The vibration assembly 150 is
located approximately at the center of the interior volume 132 between
the first end 136 and the second end 138 of the roller drum 120. The
vibration assembly 150 includes a first eccentric member 152 and a second
eccentric member 154 that can rotate with respect to each other to
generate a vibratory force within the roller drum 120. The first and
second eccentric members 152, 154 may be substantially identical and may
include a respective first elongated eccentric shaft 160 and a second
elongated eccentric shaft 162 that define a respective first eccentric
axis 164 and a second eccentric axis 166. Formed mid-length along the
first eccentric shaft 160 is a first eccentric mass 168 that is offset or
eccentric from the first eccentric axis 164. A similar second eccentric
mass 169 protrudes from the second eccentric shaft 162 so as to be offset
from the second eccentric axis 166. The eccentric masses 168, 169 can
have equal mass and an equal offset distance from their respective
eccentric axes 164, 166. The first and second eccentric members 152, 154
can be made from any suitable material that is sufficiently rigid such as
steel or iron.

[0020] The first and second eccentric members 152, 154 are arranged such
that their first and second eccentric axes 164, 166 are generally
parallel to each other. The first and second eccentric members 152, 154
also are oriented vertically within the interior volume 132 of the roller
drum 120 so that the first and second eccentric axes 164, 166 are
perpendicular to the drum axis 134 and are also generally perpendicular
to the surface 102. The first and second eccentric members 152, 154 can
be axially spaced apart from each other along the drum axis 134 with the
first eccentric member disposed toward the first end 136 of the roller
drum 120 and the second eccentric member disposed toward the second end
138. The first and second eccentric members 152, 154 may also be oriented
such that the first and second eccentric masses 168, 169 are vertically
aligned with the drum axis line 134.

[0021] To support the vertically oriented first and second eccentric
members 152, 154 in the interior volume 132 of the roller drum 120, the
vibration assembly 150 can included a cage-like framework 170. To enable
the first eccentric member 152 to rotate within the roller drum 120, a
first set of shaft bearings 172 can be provided at the top and bottom of
the first eccentric shaft 160 and can rotatably connect the first
eccentric member with the framework 170. A second set of shaft bearings
173 can be similarly provided at the top and bottom of the second
eccentric shaft 162 to rotatably connect the second eccentric member 154
to the framework 170.

[0022] To cause or drive rotation of the first and second eccentric
members 152, 154, the vibration assembly 150 can include a drive motor
174 mounted to the framework 170. The drive motor 174 can be a
hydraulically activated motor, an electro-magnetically activated motor,
or can be powered by some other method. In the illustrated embodiment,
the drive motor 174 is oriented toward the first end 136 of the roller
drum and is co-axial with the drum axis 134, but in other embodiments the
drive motor could be disposed at other positions within the interior
volume 132. The drive motor 174 includes a rotatable drive shaft 176 that
can define a drive motor axis 178. In FIG. 2, the drive motor axis 178 is
parallel to and indicated by dashed lines superimposed over the drum axis
134. In this orientation, the drive motor axis 178 is perpendicular to
the first and second eccentric axes 164, 166.

[0023] To redirect the rotational force delivered by the drive motor 174,
the vibration assembly 150 may have a drive train that includes a first
bevel gear 180 disposed on the end of the drive shaft 176. The first
bevel gear 180 cooperates or engages with a second bevel gear 182
disposed on the lower end of the first eccentric shaft 160. As will be
appreciated by those of skill in the art, cooperation between the first
and second bevel gears 180, 182 re-orientates the rotational force from
the drive motor 174 approximately 90° degrees from rotation with
respect to the drive motor axis 178 to rotation with respect to the first
eccentric axis 164. Operation of the drive motor 174 thereby causes
rotation of the first eccentric member 152 with respect to the first
eccentric axis 164. To communicate the rotational force to the second
eccentric member 154, a first transmission gear 184 can be disposed on
the lower end of the first eccentric shaft 160 and can cooperatively
engage a second transmission gear 186 on the lower end of the second
eccentric shaft 162. The first and second transmission gears 184, 186 may
be identical with the same diameter and number of teeth so that the
rotational speed of the first and second eccentric members 152, 154 in
RPMs is identical and maintained in sync. In other embodiments, the
vibration assembly can be belt-driven utilizing drive belts to transmit
the rotational force from the drive motor to the eccentric members.

[0024] To maintain the vertical and perpendicular orientation of the first
and second eccentric members 152, 154 with respect to the surface 102 and
the drum axis 134 as the roller drum 120 rolls over the surface, the
roller drum may be enabled to rotate about the drum axis independently of
the vibration assembly 150. This can be accomplished by a bearing
assembly 190 that supports the vibration assembly 150 within the interior
volume 132 of the roller drum. The bearing assembly 190 includes a first
assembly bearing 192 disposed toward the first end 136 of the roller drum
120 that attaches to and connects the framework 170 and the internal
structure of the drum shell 130. A second assembly bearing 194 disposed
toward the second end 138 of the roller drum 120 also connects the
framework 170 and the internal structure of the drum shell 130. This
arrangement allows for independent rotation of the roller drum 120 about
the internally situated but comparatively stationary vibration assembly
150.

[0025] Referring to FIG. 3, when the drive motor is activated it will
cause the first and second eccentric members 152, 154 to rotate about
their respective first and second eccentric axes 164, 166 and with
respect to each other and to the roller drum 120. The speed of rotation,
or angular velocity w, can be determined by the speed of the drive motor
and the gear ratio between the bevel gears and/or transmission gears. The
transmission gears can be set so that the first and second eccentric
members rotate in opposite rotational directions, i.e., clockwise and
counter-clockwise, as indicated by arrows 200, 202. In the embodiments
where the transmission gears are identical in order to produce synced
rotation, both the first and second eccentric members will spin at the
same angular velocity w. The eccentric members 152, 154 can be arranged
180° out of phase with each other such that when the first
eccentric mass 168 is directed toward the first end 136 of the roller
drum 120, the second eccentric mass 169 is directed toward the opposite
second end 138. Because the transmission gears spin both eccentric
members at the same angular velocity w, the first and second eccentric
members are locked into the 180° phase relationship.

[0026] Because the eccentric masses 168, 169 are radially offset from the
respective first and second eccentric axes 164, 166, the eccentric
members 152, 154 are unbalanced and their rotation will produce a moment
or centripetal force, herein referred to as an eccentric force. The
eccentric force is generally a function of Equation (1):

F=m*r*ω2 (1)

Wherein m is the eccentrically offset mass, r is the distance between the
center of mass of the offset eccentric mass and the eccentric axis of the
eccentric shaft, and ω as stated above is the angular velocity.
Rotation of the first eccentric member 152 produces a first eccentric
force 210 and rotation of the second eccentric member produces a second
eccentric force 212. The direction of the eccentric forces 210, 212 is
radially outward from the respective first and second eccentric axes 164,
166 and angularly changes with the angular position of the first and
second eccentric masses 168, 169. Hence, as the angular position of the
first eccentric mass 168 rotates 90° from a first position
indicated by solid lines to a second position indicated by dashed lines,
the direction of the first eccentric force 210 likewise changes as also
indicated by dashed lines. As illustrated in FIG. 3, the same angular
change occurs with respect to the second eccentric mass 169 and second
eccentric force 212.

[0027] Because the first and second eccentric members 152, 154 are in a
phase relationship in which they are 180° out of phase with one
another, the first and second eccentric forces 210, 212 can combine or
counteract with one another depending upon the angular orientation of the
eccentric members. For example, when the first and second eccentric
members 152, 154 are in the first position indicated by solid lines in
FIG. 3, the first and second eccentric forces 210, 212 are in opposite
directions and cancel each other. In this position, the directions of the
eccentric forces 210, 212 are parallel to the drum axis 134 and
perpendicular to the direction of travel 124 of the compactor. The
canceling eccentric forces 210, 212 thereby generate a reduced or minimum
vibratory force 220, represented as an arrow, that is generally traverse
to the direction of travel 124.

[0028] When the first and second eccentric members 152, 154 rotate to the
second position indicated by dashed lines in FIG. 3, the first and second
eccentric forces 210, 212 align together in the same, parallel direction
and combine with each other. In this position, the direction of the
eccentric forces 210, 212 is also parallel to the direction of travel 124
but perpendicular to the drum axis 134. Hence, the combining first and
second eccentric forces 210, 212 generate an increased or maximum
vibratory force 222, also represent as an arrow, generally along the
direction of travel 124. As the first and second eccentric members 152,
154 rotate another 90° so that the first and second eccentric
masses 168, 169 are directed toward each other, it will be appreciated
that the eccentric forces 210, 212 again cancel each other and produce a
reduced or minimum vibratory force parallel to and aligned along the drum
axis 134. Hence, as the eccentric members 152, 154 rotate by 90°
angular increments, they alternately cancel and combine to generate
minimum or maximum vibratory forces.

[0029] Table 1 represents the angular position of the eccentric members
and the generation of the vibratory force at each position and in the
various directions with respect to the compactor machine. In Table 1, the
first position represents the first position of the eccentric members
152, 154 indicated by solid lines in FIG. 3 and the second position
represents the second position of the eccentric members indicated by
dashed lines.

[0030] Referring to FIGS. 2 and 3, the continued and constant rotation of
the eccentric members 152, 154 in synch with each other will generate
harmonic, oscillating vibratory forces within the roller drum 120 which
are imparted to the surface 102 over which the roller drum travels. As
the eccentric members rotate in phase through a 360° rotation, the
generated vibratory forces will oscillate through one complete phase or
period and thus the vibratory forces can be represented as a sinusoidal,
harmonic function or curve. The speed or frequency ω of the
harmonic vibratory forces is directly related to the speed of the drive
motor and can be adjustably controlled by the onboard controller 118
illustrated in FIG. 1. The amplitude or magnitude of the vibratory forces
are a function of the mass of the eccentric members and their offset
distance from their respective eccentric axes.

[0031] Referring back to FIG. 2, to maintain the vibration assembly 150 in
a stationary position as the roller drum 120 rotates about the drum axis
134, in an embodiment the vibration assembly can be fixedly connected to
the frame of the compactor machine. In particular, the first flange leg
128 and second flange leg 129 can each include a respective first
extension 140 and second extension 142 that extend into the interior
volume 132 of the cylindrical roller drum 120 from the respective first
end 136 and second end 138. The first extension 140 and the second
extension 142 can attach to the framework 170 of the vibration assembly
150 by, for example, welding. Due to the fixed attachment, the vibration
assembly 150 and the first and second vertically oriented eccentric
members 152, 154 therein remain in fixed orientation as the drum shell
rolls over the surface 102. In a further embodiment, the roller drum 120
can be rotatably coupled to the frame of the compactor machine by a first
drum bearing 144 and a second drum bearing 146 that rotatably
interconnects the internal structure of the drum shell 130 to the
respective first and second flange legs 128, 129.

[0032] In another embodiment, illustrated in FIG. 4, the vibration
assembly 150, as opposed to being fixed to the frame of the compactor
machine, can pivot about the drum axis 134 to adjust the angular position
of the first and second eccentric members 152, 154 with respect to the
surface 102. Because the framework 170 is connected to the bearing
assembly 190, the bearing assembly can be made to pivot 10° or so
with respect to the surface 102 such that the angular orientation of the
first and second eccentric members 152, 154, shown in solid lines, are
changed from being truly vertical to being partially directed toward the
surface 102. In this position, the vibratory forces 240, represented as
an arrow, generated by the eccentric members 152, 154 are no longer
perfectly aligned with the direction of travel 124 but can include or
generate a component that is angularly directed toward the surface 102 in
addition to a component aligned with the direction of travel. The bearing
assembly 190 can maintain the eccentric members 152, 154 in this angular
position as the drum shell 130 of the roller drum 120 continues to rotate
around the drum axis 134 independently of the vibration assembly 150. In
a further embodiment, the bearing assembly 190 can pivot the eccentric
members 152, 154, illustrated in dashed lines, in the reverse angular
direction so that the eccentric members can have an angular orientation
with respect to the surface 102 of, for example, -10°.

[0033] In a further embodiment, illustrated in FIG. 5, the vibratory
compactor 300 can be configured as a work tool attachment that can be
attached to and either hauled behind or pushed forward of another
self-propelling machine that travels over the surface 302 to be
compacted. The vibratory compactor 300 includes an elongated cylindrical
roller drum 320 that defines and can rotate about a drum axis 334. To
attach the vibratory compactor 300 to the machine, a bifurcated
attachment device 306 is included that extends around the first end 336
and second end 338 of the roller drum 320 and connects to the roller drum
in a manner that enables the roller drum to rotate about the drum axis
334.

[0034] The vibration assembly 350 can also be disposed inside the interior
volume 332 of the roller drum 320. The vibration assembly 350 includes a
first eccentric member 352 and a second eccentric member 354 that are
maintained in a vertical position with respect to the surface over which
the roller drum 320 travels. The first eccentric member 352 defines a
first eccentric axis 364 and the second eccentric member 354 includes a
second eccentric axis 366. Due to the upright, vertical orientation of
the first and second eccentric members 352, 354, the first and second
axes 364, 366 are perpendicular to the drum axis 334 and the direction of
travel 324 of the vibratory compactor 300. To enable the roller drum 320
to rotate about the drum axis 334 while maintaining the vertical
orientation of the eccentric members 352, 354, a bearing assembly 390 is
disposed inside the interior volume 332. The bearing assembly 390
includes a first assembly bearing 392 and a second assembly bearing 394
that connects the interior structure of the drum shell 330 with a
framework 370 that in turn connects to the first and second eccentric
members 352, 354. To rotate the first and second eccentric members 352,
354 and generate the vibratory forces, the vibratory compactor can
include various gears, bearings and a drive motor as described above.

INDUSTRIAL APPLICABILITY

[0035] As explained above, the present disclosure is applicable to
compacting and densifying a loose material such as freshly spread asphalt
disposed over a surface. Referring to FIG. 3, the compactor machine 100
can travel over the surface 102. As the compactor machine 100 travels the
forward roller drum 120 which is in rolling contact with the surface 102
rotates about the drum axis 134 that is orientated perpendicularly to the
direction of travel 124. The vibrator assembly 150 is disposed inside the
rotating roller drum 320 and includes the vertical first and second
eccentric members 152, 154 whose respective first and second eccentric
axes are perpendicular to the drum axis 134. The vertical orientation of
the first and second eccentric members 152, 154 is maintained as the
roller drum 120 independently rotates about the vibrator assembly 150.

[0036] As the eccentric members 152, 154 rotate or spin around their
respective eccentric axes, they produce the centripetal forces or
eccentric forces 212, 210 that combine or cancel so as to generate
alternating increased or reduced, i.e., maximum or minimum, vibratory
forces within the roller drum 120. The increased or maximum vibratory
force 222 is aligned and parallel with the direction of travel 124. It
will be appreciated that aligning the maximum vibratory force along the
direction of travel 124 will create a general forward-and-reverse, or
back-and-forth, vibrations in the roller drum 120 that will in turn
impart the same vibrations to the surface 102. Back-and-forth vibrations
are beneficial in compacting asphalt, soil, and similar materials as they
tend to both shift back and forth and compress downward the loose
material with respect to the surface. Hence, the asphalt tends to densify
in multiple directions.

[0037] The reduced or minimum vibratory force 220, in contrast, is aligned
and parallel with the drum axis 134 and therefore perpendicular to the
direction of travel 124. Aligning the minimum vibratory force with the
drum axis 134 minimizes the side-to-side vibrations or forces imparted to
the roller. This is may be beneficial in maintaining the structural
integrity of the compactor machine 100 because such side-to-side
vibrations tend to be damaging to the machine. For example, referring to
FIG. 2, the side-to-side movement may damage the bearings 144, 146 that
rotatably connect the roller drum 120 with the first flange leg 128 and
the second flange leg 129. Additionally, it will be appreciated that the
side-to-side vibrations may detract the compactor machine from the
intended direction of travel 124 that is typically perpendicular to the
side-to-side vibrations. Reducing or minimizing the vibratory forces in
the side-to-side direction can therefore improve the longevity of the
compactor machine.

[0038] Referring to FIG. 4, it will be appreciated that pivoting the
vibration assembly 150 with respect to the drum axis 134 directs the
vibratory forces 240 both in the back-and-forth direction and downwards
toward the surface. Hence, the vibration forces 240 provide both a
shifting motion and a compressing force to the loose material being
compacted while still reducing side-to-side vibrations.

[0039] It will be appreciated that the foregoing description provides
examples of the disclosed system and technique. However, it is
contemplated that other implementations of the disclosure may differ in
detail from the foregoing examples. All references to the disclosure or
examples thereof are intended to reference the particular example being
discussed at that point and are not intended to imply any limitation as
to the scope of the disclosure more generally. All language of
distinction and disparagement with respect to certain features is
intended to indicate a lack of preference for those features, but not to
exclude such from the scope of the disclosure entirely unless otherwise
indicated.

[0040] Recitation of ranges of values herein are merely intended to serve
as a shorthand method of referring individually to each separate value
falling within the range, unless otherwise indicated herein, and each
separate value is incorporated into the specification as if it were
individually recited herein. All methods described herein can be
performed in any suitable order unless otherwise indicated herein or
otherwise clearly contradicted by context.

Patent applications by Eric S. Engelmann, Delano, MN US

Patent applications by John L. Marsolek, Watertown, MN US

Patent applications by Caterpillar Inc.

Patent applications in class In situ treatment of earth or roadway

Patent applications in all subclasses In situ treatment of earth or roadway